The long-term goal of this research is to elucidate the molecular and cellular mechanisms that ensure potassium (K+) channels assemble with the appropriate membrane-embedded regulatory subunits for proper physiological function. N-glycosylation is a vital co- and post-translational modification that facilitates the assembly and trafficking of K+ channel subunits. Mutations that block glycosylation of KCNE K+ regulatory subunits have been directly linked to the genetic and drug-induced forms of cardiac arrhythmias (Long QT Syndrome). Accordingly, the two aims of this proposal investigate K+ channel subunit glycosylation in the ER, Golgi and plasma membrane: (1) We will determine the molecular and cellular bases of K+ channel subunit co- and post-translational N-glycosylation. (2) We will reengineer the cell's glycocalyx to fluorescently visualize K+ efflux from living cells.